The aim of this proposal is to improve our understanding of factors related to cognitive health of school-aged children by examining the effects of a 9-month exercise intervention on basic and applied aspects of cognition in preadolescent children. From a basic measurement perspective, event-related brain potentials (i.e., neuroelectric activity in response to, or in preparation for, a stimulus or response) and behavioral (i.e., reaction time, response accuracy) indices of cognition will be studied during several tasks aimed at assessing various aspects of executive control (i.e., a subset of processes concerned with the selection, scheduling, and coordination of computational processes responsible for perception, memory, and action). Preliminary research has observed faster and more efficient performance in high-fit, relative to low-fit, children and adults using neuroelectric measures that reflect attentional allocation to environmental stimuli (i.e., P3) and response monitoring processes (i.e., ERN, Pe), along with behavioral measures that reflect response speed and accuracy. These preliminary findings indicate greater top-down attentional control may be associated with increases in physical activity. From an applied measurement perspective, preliminary research has found that children with greater aerobic fitness perform better on standardized achievement tests of reading and mathematics, compared to children with lower aerobic fitness, suggesting that exercise may be related to academic performance in an applied school setting. To date, no causal evidence exists regarding the effects of physical activity on neuroelectric, behavioral, or applied school performance indices of cognition in children. Accordingly, this proposal investigates an aerobic physical activity training intervention on these measures of cognition using three tasks (single stimulus, Go/NoGo, flanker) that require variable amounts of executive control, and on the Illinois Standardized Achievement Test using a randomized control design in which particiants are assigned to an afterschool physical activity program or a wait-list control group. Given recent trends identifying decreased levels of physical activity and health status in preadolescents, the understanding of the potential benefits of physical activity on cognition is of great interest. It is imperative that factors positively influencing cognitive function of children be examined to maximize health and effective functioning of individuals as they progress through the lifespan. PUBLIC HEALTH RELEVANCE: recent trends have identified decreasing levels of physical activity, fitness, and health in preadolescent children. Examining factors, such as physical activity behavior and aerobic fitness that positively influence cognitive health of school-age children are important for improving school performance, maximizing health, and improving the overall functioning of individuals as they progress through the human lifespan. A sample of preadolescent children from the Urbana, Illinois elementary school system will be randomly assigned to a 9- month afterschool program that focuses on either aerobic exercise or wait-list control group to determine the effects of physical activity on basic and applied aspects of cognition. Changes in neuroelectric and behavioral indices of cognitive function and performance on standardized academic achievement tests of mathematics and reading will be examined as a function of participation in the intervention. Preliminary research supports that physical activity is positively associated with basic and applied aspects of cognition, with a stronger relationship for tasks requiring extensive amounts of executive control. However, previous research has mainly focused on older adults, and little research has examined the relationship between physical activity and executive control in children. These findings will provide lifestyle considerations for children to improve their cognitive health across the lifespan.